Reactor for plasma-based atomic layer etching of materials

Abstract

Plasma-based atomic layer etching of materials may be of benefit to various semiconductor manufacturing and related technologies. For example, plasma-based atomic layer etching of materials may be beneficial for adding and/or removing angstrom thick layers from a surface in advanced semiconductor manufacturing and related technologies that increasingly demand atomistic surface engineering. A method may include depositing a controlled amount of a chemical precursor on an unmodified surface layer of a substrate to create a chemical precursor layer and a modified surface layer. The method may also include selectively removing a portion of the chemical precursor layer, a portion of the modified surface layer and a controlled portion of the substrate. Further, the controlled portion may be removed to a depth ranging from about 1/10 of an angstrom to about 1 nm. Additionally, the deposition and selective removal may be performed under a plasma environment.

We claim: 
     
       1. A method, comprising:
 depositing a controlled amount of a chemical precursor on an unmodified surface layer of a substrate to create a chemical precursor layer and a modified surface layer, the modified surface layer created by reactions between the unmodified surface layer and the chemical precursor; and 
 selectively removing a portion of the chemical precursor layer, a portion of the modified surface layer, and a controlled portion of the substrate, 
 wherein the controlled portion is removed to a depth ranging from about 1/10 of an angstrom to about 1 nm, and 
 wherein the deposition and selective removal are performed under a plasma environment. 
 
     
     
       2. The method of  claim 1 , further comprising cyclically repeating the deposition of the controlled amount of the chemical precursor and the selective removal of the portion of the chemical precursor layer, the portion of the modified surface layer, and the controlled portion of the substrate until a desired overall etching depth is achieved. 
     
     
       3. The method of  claim 1 , further comprising controlling a rate of removal of material in the selective removal process. 
     
     
       4. The method of  claim 1 , wherein the chemical precursor is deposited in a plurality of pulse lengths using predetermined amounts of time and mass flows, and wherein the selective removal also accompanies the chemical precursor deposited in the cycles. 
     
     
       5. The method of  claim 4 , wherein a thickness of the deposited chemical precursor is about 1 angstrom to about 3 nm. 
     
     
       6. The method of  claim 1 , wherein the substrate comprises at least one material that shows chemically induced etching in the presence of low energy ion bombardment and the chemical precursor. 
     
     
       7. The method of  claim 1 , wherein the substrate comprises at least one of SiO2, Si3N4, c-Si, amorphous Si, poly-crystalline Si, SixGe1−x, GaAs or other group III-V semiconductors, GaAlxAs1−x, InGaAs1−x, GaPxAs1−x, or the oxides, nitrides, or oxynitrides of the above materials. 
     
     
       8. The method of  claim 1 , wherein the substrate comprises a native oxide layer on the surface of the substrate, and wherein the native oxide layer has a thickness of about 1/10 of 1 nm to about 10 nm. 
     
     
       9. The method of  claim 1 , wherein the substrate comprises high-k dielectric films. 
     
     
       10. The method of  claim 1 , wherein the substrate comprises low-k dielectric films, with or without nanopores. 
     
     
       11. The method of  claim 9 , wherein the substrate comprises at least one of SiCOH, SiOyFx, or polymeric low-k dielectric films, with or without nanopores. 
     
     
       12. The method of  claim 9 , wherein the high-k dielectric films comprises Al2O3, HfO2, or Hf-silicate. 
     
     
       13. The method of  claim 1 , wherein the substrate comprises at least one of graphene, graphite and other forms of carbon, deposited on a Si or silicon-on-insulator substrate. 
     
     
       14. The method of  claim 1 , further comprising coupling a plasma system to deposit the controlled amount of the chemical precursor, and selectively remove the portion of the chemical precursor layer, the portion of the modified surface layer, and the controlled portion of the substrate. 
     
     
       15. The method of  claim 1 , further comprising applying a bias potential to the substrate at a level configured to increase ion energies, wherein the bias potential is synchronized to the deposition of the controlled amount of the chemical precursor. 
     
     
       16. The method of  claim 1 , wherein the chemical precursor comprises at least one of a fluorocarbon gas, oxygen-, or bromine-based gas. 
     
     
       17. The method of  claim 16 , wherein the fluorocarbon gas comprises at least one of the hydrofluorocarbon gas C n F m H 1  precursors or isomers thereof, or any C n O m F 1  gas precursors or isomers thereof, either alone or with admixtures of either N 2 , H 2 , O 2 , CO, CO 2 , noble gases, CH 4 , or SiF 4 , alone, or in combination.